Fast rotating dipole array inducing large dielectric response in a Ruddlesden–Popper hybrid perovskite ferroelastic

Abstract

Dynamic functional materials have attracted increasing interest owing to their broad potential applications in the field of flexible smart. Molecular rotors are a good platform to achieve functionality because of the intrinsic movement of the internal components. Herein, we report a two-dimensional (2D) Ruddlesden–Popper (RP) type hybrid perovskite ferroelastic (TFCA)₂CdCl₄ (1; TFCA = 2-fluoro-1-amino-pyrrolidium) showing T_c (402 K) and spontaneous strain (0.071). Impressively, the rapid rotating motions of the polar rotors lead to the fast reorientation of the dipoles resulting in a large dielectric response. The switching on–off ratio of dielectric anomaly is more than 100 (ε′_HTP/ε′_LTP > 100) at a high-frequency electric field (1 MHz). This study reveals that the 2D RP hybrid perovskite molecular rotor platform provides a new avenue to explore dynamic functional materials.